An electric power conversion unit 2 for driving a pump 3 run by electric power generated by a solar panel 1, a storage battery 5 connected to the solar panel 1 via the switch 6, and a controller 7 for controlling the electric power conversion unit 2 and the switch 6 are provided. The controller 7 closes the switch 6 during any period when the amount of insolation is large and performs the maximum power point tracking control of the solar panel 1, and otherwise, controls the electric power conversion unit 2 to drive at one of plural fixed frequencies in dependence upon an output voltage from the solar panel 1 by closing the switch 6. Accordingly, it is possible to utilize output from an unstable electric power supply efficiently, such as a solar cell, thereby providing a reliable electric motor driving apparatus having a simple configuration and a control method therefor.
Legal claims defining the scope of protection, as filed with the USPTO.
1. An electric power supplying apparatus comprising: an unstable power supply that generates electric power; an electric power storage unit that is connected to said unstable electric power supply in parallel; a switch that is connected between said unstable electric power supply and said electric power storage unit in series; a converter that converts electric power supplied from said unstable electric power supply, or from both said unstable electric power supply and said electric power storage unit, to electric power which is suitable for a load so as to supply the converted electric power to the load; and a controller that controls opening and closing of said switch and controls an operation of said converter based on an output from the unstable electric power supply so as to efficiently operate the unstable electric power supply, wherein said controller opens said switch during an independent-driving mode period and closes said switch outside of the independent-driving mode period.
2. The apparatus according to claim 1 , wherein the load is an electric pump.
3. The apparatus according to claim 1 , wherein said electric power storage unit is a nickel-hydrogen battery or an electric double layer capacitor.
4. The apparatus according to claim 1 , wherein said unstable electric power supply is a solar power generator or a wind power generator.
5. An electric power supplying apparatus comprising: an unstable power supply that generates electric power; an electric power storage unit that is connected to said unstable electric power supply in parallel; a switch that is connected between said unstable electric power supply and said electric power storage means in series; a converter that converts electric power supplied form said unstable electric power supply, or from both said unstable electric power supply and said electric power storage unit, to electric power which is suitable for a load so as to supply the converted electric power to the load; and a controller that controls opening and closing of said switch and controls operation of said converter based on an output from the unstable electric power supply so as to efficiently operate the unstable electric power supply, wherein said controller opens said switch when an output power from said unstable power supply exceeds a predetermined value and closes said switch when the output power is equal or less than the predetermined value.
6. The apparatus according to claim 1 , wherein, when said switch is closed, said controller controls the operation of said converter if an output voltage from said unstable electric power supply exceeds a first predetermined voltage, and stops the operation of said converter if the output voltage drops below a second predetermined voltage.
7. The apparatus according to claim 1 , wherein said controller controls the operation of said converter to track a maximum power point of said unstable electric power supply when said switch is open, and controls said converter to output alternating current electric power at a predetermined frequency when said switch is closed.
8. The apparatus according to claim 1 , wherein said controller comprises a detector that detects an output voltage and an output current from the unstable electric power supply.
9. A control method of controlling an electric power supplying apparatus, to efficiently operate an unstable power supply which generates electric power, having: an electric power storage unit that is connected to the unstable electric power supply in parallel; a switch that is connected between the unstable electric power supply and the electric power storage unit in series; and a converter that converts electric power supplied from the unstable electric power supply, or from both the unstable electric power supply and the electric power storage unit, to electric power which is suitable for a load so as to supply the converted electric power to the load, said method comprising the steps of: opening the switch during an independent-driving mode period; closing the switch outside of the independent-driving mode period; and controlling an operation of the converter depending upon an output from the unstable electric power supply.
10. The control method according to claim 9 , wherein, when the switch is closed, in said controlling step, the converter is operated when an output voltage from the unstable electric power supply exceeds a first predetermined voltage, and the operation of the converter is stopped when the output voltage drops below a second predetermined voltage.
11. The control method according to claim 9 , wherein in said controlling step, the operation of the converter is controlled to track a maximum power point of the unstable electric power supply when the switch is opened, and to output alternating current electric power at a predetermined frequency when the switch is closed.
12. A control method of controlling an electric power supplying apparatus, to efficiently operate an unstable power supply which generates electric power, having: an electric power storage unit that is connected to the unstable electric power supply in parallel; a switch that is connected between the unstable electric power supply and the electric power storage unit in series; and a converter that converts electric power supplied from the unstable electric power supply, or from both the unstable electric power supply and the electric power storage unit, to electric power which is suitable for a load so as to supply the converted electric power to the load, said method comprising the steps of: opening the switch when output electric power of the unstable electric power supply exceeds a predetermined value; closing the switch when the output electric power is equal or less than the predetermined value; and controlling an operation of the converter depending upon an output voltage of the unstable electric power supply.
13. The control method according to claim 12 , wherein, when the switch is closed, in said controlling step, the converter is operated when an output voltage from the unstable electric power supply exceeds a first predetermined voltage, and the operation of the converter is stopped when the output voltage drops below a second predetermined voltage.
14. The control method according to claim 12 , wherein in said controlling step, the operation of the converter is controlled to track a maximum power point of the unstable electric power supply when the switch is opened, and to output alternating current electric power at a predetermined frequency when the switch is closed.
15. The apparatus according to claim 5 , wherein, when said switch is closed, said controller controls the operation of said converter if an output voltage from said unstable electric power supply exceeds a first predetermined voltage, and stops the operation of said converter if the output voltage drops below a second predetermined voltage.
16. The apparatus according to claim 5 , wherein said controller controls the operation of said converter to track a maximum power point of said unstable electric power supply when said switch is open, and controls said converter to output alternating current electric power at a predetermined frequency when said switch is closed.
17. The apparatus according to claim 5 , wherein said controller comprises a detector which detect an output voltage and an output current from said unstable electric power supply.
18. The apparatus according to claim 5 , wherein the load is an electric pump.
19. The apparatus according to claim 5 , wherein said electric power storage is a nickel-hydrogen battery or an electric double layer capacitor.
20. The apparatus according to claim 5 , wherein said unstable electric power supply is a solar power generator or a wind power generator.
21. An electric supplying apparatus comprising: an unstable power supply which generates electric power; an electric power storage which is connected to said unstable electric power supply in parallel; a switch which is connected between said unstable electric power supply and said electric power storage in series; a power converter which converts electric power supplied from said unstable electric power supply, or from both said unstable electric power supply and said electric power storage, to electric power which is suitable for a load so as to supply the converted electric power to the load; and a controller which controls opening and closing of said switch and controls an operation of said power converter based on an output from said unstable electric power supply so as to efficiently operate said unstable electric power supply, wherein, when said switch is closed, said controller controls the operation of said converter if an output voltage from said unstable electric power supply exceeds a first predetermined voltage, and stops the operation of said converter if the output voltage drops below a second predetermined voltage.
22. The apparatus according to claim 21 , wherein the load is an electric pump.
23. The apparatus according to claim 21 , wherein said electric power storage is a nickel-hydrogen battery or an electric double layer capacitor.
24. The apparatus according to claim 21 , wherein said unstable electric power supply is a solar power generator or a wind power generator.
25. The apparatus according to claim 21 , wherein said controller comprises a detector which detects an output voltage and an output current from said unstable electric power supply.
26. An electric power supplying apparatus comprising: an unstable power supply which generates electric power; an electric power storage which is connected to said unstable electric power supply in parallel; a switch which is connected between said unstable electric power supply and said electric power storage in series; a power converter which converts electric power supplied from said unstable electric power supply, or from both said unstable electric power supply and said electric power storage, to electric power which is suitable for a load so as to supply the converted electric power to the load; and a controller which controls opening and closing of said switch and controls an operation of said power converter based on an output from said unstable electri power supply so as to efficiently operate said unstable electric power supply, wherein said controller controls the operation of said converter to track a maximum power point of said unstable electric power supply when said switch is open, and controls said converter to output alternating current electric power at a predetermined frequency when said switch is closed.
27. The apparatus according to claim 26 , wherein the load is an electric pump.
28. The apparatus according to claim 26 , wherein said electric power storage is a nickel-hydrogen battery or an electric double layer capacitor.
29. The apparatus according to claim 26 , wherein said unstable electric power supply is a solar power generator or a wind power generator.
30. The apparatus according to claim 26 , wherein said controller comprises a detector which detector which detects an output voltage and an output current from said unstable electric power supply.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
August 19, 1997
July 8, 2003
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